I didn’t understand “10. It’s telling you to go backwards, so 4710.”
It’s telling me go backwards? What’s that? I just see there some patterns made out of musical notes. Nothing else. What am I supposed to see there? How come do you understand from that bunch of notes that the code is 4710?

You need to look in the negative space between the music notes. It makes up those numbers. Then there is an arrow in the upper right pointing left, so you know you have to put the numbers in order from right to left.